What is Solar Power?

The sun provides energy in the form of light and heat. We have traditionally used the sun to heat water and food and to dry clothes and now we can use it to produce electricity. The energy produced from using the sun’s energy is called solar power.

Solar power consists of two categories:

• Solar Thermal Energy; and
• Solar Photovoltaic Energy

Solar energy is Australia’s largest energy resource, although it is intermittent and relies on climate conditions.

Solar Thermal Energy

Solar Thermal Energy refers to the use of the sun's energy for heating and cooling things like water. This heated water can either be used directly or to create steam to drive the turbines that generate electricity.

Climate conditions have a large impact on the effectiveness of Solar Thermal Energy and whilst Australia has a great climate for it, there are not a lot of active examples of it here.

Most solar hot water systems use solar collectors to absorb energy from the sun. Water is heated by the sun as it passes through the collectors. It then flows into an insulated storage tank for later use. In passive systems, water flows unassisted between the collectors and the tank. In active systems, water is pumped between the collectors and the tank. The storage tank is usually fitted with an electric or gas booster that heats the water when sunlight is insufficient. Some solar water heaters also have frost protection to prevent damage in frost prone areas.

Solar Photovoltaic Energy

Solar Photovoltaic Energy refers to the conversion of sunlight from solar cells to electricity, which can be used in homes and buildings just like the current electricity you are getting from the energy grid. The same technology is used to power things like calculators or remote telephones.

Photovoltaic “cells” are made up with layers of silicon that contain specific chemicals. Electrons in these layers are charged by direct sunlight and once energised, these electrons travel through the cell into a wire creating an electric current.

Solar power systems are free of pollution and noise, which makes them the ideal renewable energy source in urban areas.

The amount of power generated by a photovoltaic cell is determined by the:

• Type and size of the material
• Intensity of the sunlight (also based on the orientation and location of the panels)
• Wavelength of the sunlight
• Season

In remote areas without access to the main electricity grid, an energy storage system is often necessary in order to have electricity even when the sun is not shining – either at night or in cloudy periods – or in quantities greater than are supplied by the solar panels. Specially designed batteries are generally used for those occasions.

Sometimes when the combination of sun and wind energy is viable, wind generators are used in conjunction with PV systems.

Advantages of Solar Power

• Sustainable energy supply
• Long lifespan
• Noiseless
• No moving parts
• Ideal for remote areas not connected to the main electricity grid (there are a lot of these areas in Australia)
• It's almost free once any equipment is installed
• More jobs created in manufacturing, installation and operation

Disadvantages of Solar Power

• It is an intermittent and diffuse source
• Photovoltaic panels require a lot of energy and create pollution during manufacturing
• The advanced technology makes it very expensive to manufacture
• Panels are hard to recycle at the end of their life

For further information on Solar power or any of the other renewable sources of energy visit www.seda.nsw.gov.au.